The survey of 250 youth workers across NSW found 90 per cent of them work with young people who are suspended from school. Of those, 82 per cent said they believed at least one of the young people they helped had been suspended unfairly.

The research by the Youth Action and Policy Association, found the reasons for suspensions included retaliating against a bully, arriving late to school on a regular basis, swearing and truanting.

It also found that there was a lack of understanding of the impact of homelessness and mental health problems on students who were suspended and that Aboriginal and Torres Strait Islander, Pacific Islander children and those with disabilities and behavioural issues were overrepresented.

The Youth Action and Policy Association called for an urgent review of the NSW school suspension policy and an increase in the number of school counsellors available to children.

It says there is only one counsellor for every 1050 students and this ratio should be lowered to one counsellor for every 500 students to adequately address the need of many disadvantaged students.

Eamon Waterford, the association's director of policy and advocacy, said a young person who is suspended from school is more than four times likely to commit a crime than if they were simply truanting from school.

He said schools interpret the suspension policy individually, leading to widely different rates of suspension between different schools in different regions of the state.

''It's clear that the school suspension system is currently not achieving its goal of changing behaviour,'' he said. ''We're calling on the Department of Education and Communities to conduct a public review of school suspension policy.''

The association has also recommended that the NSW government develop new behaviour management options at schools and re-integration programs. Mr Waterford said the school suspension policy should also be developed to take the social, cultural and economic background of students into account.

Under the existing policy, students can be suspended for four to 20 days at the discretion of their school principal. School suspensions have risen by more than a third over the past six years but do little to improve the behaviour of children, new research has found.

Another recently released study by Uniting Care, analysed the NSW Department of Education's figures.

It showed the number of long-term suspensions - lasting five to 20 days - had increased by 36 per cent in six years, while suspensions increased from 12,326 in 2006 to 16,814 last year.

A spokesman for the NSW Department of Education said schools had a duty of care to protect students, teachers and other staff from violent students and those involved in criminal activity.

''Suspension is not intended as a punishment,'' the spokesman said.

''Suspension is only one strategy to manage inappropriate student behaviour within a school's student welfare and discipline policies.''